Designed environments are built to house groups or populations of house mice of Norway rats. Through the locations of resources, response eliciting opportunities, partial barriers and travel routes, environments are designed to influence: choice, frequency of social interaction, cooperation, privacy, group integrity, formation of communication networks, identity differentiation, and perceptual and motor skills contributing to coping and creativity. Such influences on behavior are realized by instituting an unambiguous environmental language through spatial and structural relationships of components and by uniqueness of texture and form related to opportunity to express each specific behavior or set of related behaviors. In essence this project represents behavior related to experimental architecture. Influence upon behavior and social organization of environmental design are assessed through strategies of inquiry incorporated in projects Z01 MH 00833 to 00836. Emphasis in this project is placed on the behavioral zoography (spatial distribution of behaviors) and upon the expression of territoriality. The scope of this project encompasses aspects of previous projects ZO1 MH 00823, 24, 29. BIBLIOGRAPHIC REFERENCE: Calhoun, J.G.: "Looking Backward" from the beautiful ones. In W.R. Klemm (Ed.): Discovery Processes in Modern Biology. Huntington, N.Y., Robert E. Krieger Publishing Co., 1977, pp. 26-65.